This invention addresses a significant and unmet medical need of providing for sensitive immunoassays which allow for advancement in the field of personalized cancer therapy. The general concept of personalized medicine for cancer has been the subject of recent reviews (Zoon K C, 2004, Toxicology Pathol. 32(Suppl 1):1-2; MacGregor J T, 2004, Toxicology Pathol. 32(Suppl 1):99-105; Carr K M et al., 2004 Hum Genomics 1:134-40). The approach of personalized medicine for cancer is to characterize the proteins or genes in the patient's tumor in order to determine the best course of therapy. For example, expression of certain genes or gene patterns at either the protein or mRNA level may predict either sensitivity or resistance to various classes of anticancer agents. Based on the expression in the patient's tumor, an agent may be selected for therapy or rejected for use in that particular patient. Table 1 lists some of the proteins whose overexpression is associated with either resistance or sensitivity of certain cancer agents.
TABLE 1Proteins whose overexpression is associated with resistance or sensitivity ofcertain agents.Prediction of Resistance or Sensivitity ofProteinProtein ClassVarious AgentsEGFRMembraneOverexpression of EGFR predictsreceptor withresponse to anti-EGFR agents such astyrosine kinasecetuximab, panitumumabactivityERCC1EnzymeOverexpression of ERCC1 predicts(Member ofresistance to platinum agents (e.g.,Nucleotidecisplatin, carboplatin, oxaliplatin)Excision Repair[Reed (2005; Clin Cancer Res 11: 6100-6102);Pathway)Lord et al. (2002, Clin Cancer Res8: 2286-91); Metzer et al., 1998, J ClinOncol 16: 309-316; Shirota et al. (2001, JClin Oncol 19: 4298-4304)]RibonucleotideEnzymeOverexpression of RRM1 predictsreductase subunit M1resistance to gemcitabine [Bergman AM(RRM1)et al., 2005 Clin Cancer Res 65: 9510-6]ThymidylateEnzymeOverexpression of TS predicts resistanceSynthase (TS)to 5-FU;High TS expression predicts non-response to raltitrexed [Farrugia et al.(2003, Clin Cancer Res 9: 792-801)]Beta-tubulin (classStructuralOverexpression of beta-tubulin (class III)III)predicts resistance to taxanes [Mozzetti etal. (2005, Clin Caner Res 11: 298-305)];Overexpression of beta-tubulin (class III)predicts resistance to vinca alkaloids[Seve et al., 2005, Clin Cancer Res11: 5481-6]
A major impediment for the advance in this field is the lack of a convenient, quick and objective assay to determine overexpression of such proteins. This invention addresses this issue.
One approach to assay expression of proteins in patient tumor tissue is to use immunohistochemical (IHC) staining of formalin fixed tumor tissue. But as pointed out by Mann et al. (2005, J Clin Oncol 22:5148-54), such an approach is time-consuming and often can give misleading results depending upon how the tissue was processed. Henson, D. E. (2005, J Natl Cancer Inst 97:1796-7) in his paper entitled: “Back to the Drawing Board on Immunhistochemistry and Predictive Markers”, indicates that with so many variables (storage of the specimen, duration of fixation, type of fixative and conditions of tissue processing) and problems associated with each of them, it is difficult to properly control IHC testing and for all laboratories to “accept and sustain [these controls] seem impossible to realize.”